ω-3 Fatty Acid Supplements May Not Improve Dry Eye Symptoms

Abstract

Meibomian gland dysfunction (MGD) is a major cause of evaporative dry eye. 1 ω-3 Fatty acid supplements are used for evaporative dry eye because they may boost levels of ω fatty acids, potentially contributing to regulation of inflammation and promotion of meibomian gland secretion. 2 Randomized clinical trials (RCTs) of ω-3 fatty acid supplements are not new. Perhaps the most well-known RCT is the Dry Eye Assessment and Management (DREAM) trial, a large RCT of 535 participants with moderate to severe dry eye at 27 clinical centers in the United States. 3 Several systematic reviews of RCTs also have evaluated this topic. For example, Downie et al 4 published a Cochrane systematic review in 2019 and concluded, based on 10 RCTs, that ω-3 may lead to (1) little to no reduction in symptoms, (2) a benefit in tear production, but a benefit that was not thought to be clinically meaningful, and (3) a reduction in tear osmolarity. Wang and colleagues recently published a systematic review in 2023 and concluded, based on 19 RCTs, that, at high doses, ω-3 fatty acids probably improve symptoms, tear production, tear stability, and tear osmolarity. 5 Both systematic reviews identified considerable inconsistency in the evidence, stemming from heterogeneous patient populations and variable outcome use. 4,5 The authors of the reviews also called for future RCTs to evaluate specific ω-3 formulation characteristics, such as dose, frequency, and composition, and for future RCTs to evaluate consistent outcomes. 4,5